The present invention relates to a variable geometry inlet for a supersonic combustion ram (scram) jet engine with single or multiple modules used to provide thrust for a hypersonic vehicle.
A scram jet engine typically requires a variable geometry inlet for operability and performance. A common approach is to use cowl inlet flap(s), whose position can be adjusted during flight. Several approaches to the design of a variable geometry inlet have been presented in the literature. They include, but are not limited to, those that incorporate in-stream strut actuation as shown in FIG. 1, a sidewall housed strut actuation as shown in FIG. 2, and a geared hinge actuation as shown in FIG. 3.
In-stream strut actuation provides a structurally efficient solution by distributing actuation loads across the width of the flap, but introduces undesirable flow disturbances in the inlet, and requires complicated sealing where the struts penetrate the body panel. Sidewall housed strut actuation eliminates the in-stream struts and their associated flow disturbances, but also requires complicated sealing where the actuation penetrates the extended sidewall structure. Geared hinge actuation eliminates the flow blockage and sealing issues, but requires a larger diameter hinge to house the gears, and is mechanically more complex.
A simple approach is required which eliminates the flow blockage of the in-stream struts, and eliminates the need for complicated seals.